FeralHeart does not display malware ads on the pages, however if you have been browsing around less carefully on the internet before, your computer could've been infected and display inappropriate ads as soon as you start up the browser or load a page.
The issue you appear to be having is not really related to the FH site, rather your computer or browser I believe.
As mentioned above, you really should do some virus scans and make sure you don't have something fishy laying around on it, or maybe let someone that is very familiar with computers to take a look at it. Something like malware ads popping up randomly shouldn't be left unattended.
If you don't have any proper antivirus installed(like you should), I'd personally suggest getting AVG Free for the time being, it does the job well, however the option of malwareBytes work too.